system-image-cli tool fails on dangling symlink

[Ben Howard]

(amd64)ubuntu@localhost:~$ system-image-cli -i
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/systemimage/helpers.py", line 253, in last_update_date
    timestamp = datetime.fromtimestamp(os.stat(LAST_UPDATE_FILE).st_mtime)
FileNotFoundError: [Errno 2] No such file or directory: '/userdata/.last_update'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/bin/system-image-cli", line 9, in <module>
    load_entry_point('system-image==3.0.1', 'console_scripts', 'system-image-cli')()
  File "/usr/lib/python3/dist-packages/systemimage/main.py", line 289, in main
    last_update=last_update_date(),
  File "/usr/lib/python3/dist-packages/systemimage/helpers.py", line 258, in last_update_date
    for path in config.ini_files)
  File "/usr/lib/python3/dist-packages/systemimage/helpers.py", line 258, in <genexpr>
    for path in config.ini_files)
  File "/usr/lib/python3.4/pathlib.py", line 1048, in stat
    return self._accessor.stat(self)
  File "/usr/lib/python3.4/pathlib.py", line 326, in wrapped
    return strfunc(str(pathobj), *args)
FileNotFoundError: [Errno 2] No such file or directory: '/etc/system-image/config.d/00_default.ini'

[Barry Warsaw (barry)]

On Sep 14, 2015, at 08:40 PM, Ben Howard wrote:

>Public bug reported:
>
>
>(amd64)ubuntu@localhost:~$ system-image-cli -i
>Traceback (most recent call last):
> File "/usr/lib/python3/dist-packages/systemimage/helpers.py", line 253, in last_update_date
> timestamp = datetime.fromtimestamp(os.stat(LAST_UPDATE_FILE).st_mtime)
>FileNotFoundError: [Errno 2] No such file or directory:
>'/userdata/.last_update'

This can be an expected exception, because it's possible for
/userdata/.last_update to be missing. That case is handled, and the real
problem is here:

>During handling of the above exception, another exception occurred:
>
>Traceback (most recent call last):
> File "/usr/bin/system-image-cli", line 9, in <module>
> load_entry_point('system-image==3.0.1', 'console_scripts', 'system-image-cli')()
> File "/usr/lib/python3/dist-packages/systemimage/main.py", line 289, in main
> last_update=last_update_date(),
> File "/usr/lib/python3/dist-packages/systemimage/helpers.py", line 258, in last_update_date
> for path in config.ini_files)
> File "/usr/lib/python3/dist-packages/systemimage/helpers.py", line 258, in <genexpr>
> for path in config.ini_files)
> File "/usr/lib/python3.4/pathlib.py", line 1048, in stat
> return self._accessor.stat(self)
> File "/usr/lib/python3.4/pathlib.py", line 326, in wrapped
> return strfunc(str(pathobj), *args)
>FileNotFoundError: [Errno 2] No such file or directory: '/etc/system-image/config.d/00_default.ini'

What happened to /etc/system-image/config.d/00_default.ini? What this is
saying is that after system-image-cli started up, this config file (or its
directory) got lost or removed. That shouldn't ever happen.

Are you able to do some live debugging?

[Ben Howard (utlemming)]

I was running "system-image-cli" via a chroot on a vanilla image; the
instance was never booted.

[Barry Warsaw (barry)]

On Sep 14, 2015, at 10:11 PM, Ben Howard wrote:

>I was running "system-image-cli" via a chroot on a vanilla image; the
>instance was never booted.

What does /etc/system-image/config.d look like?

[Oliver Grawert (ogra)]

seems like system-image-common 3.x stopped shipping anything in /etc in the binary deb (i see it in the 2.x series in that package but not in 3.x anymore)

[Oliver Grawert (ogra)]

note that we use 3.x also in the 15.04 snappy builds, so 15.04 edge is broken the same way

[Oliver Grawert (ogra)]

i just found that simply removing /etc/system-image/config.d/00_default.ini is enough to make it work fine (we ship a /etc/system-image/config.d/20_snappy.ini that provides all bits and pieces needed, the default.ini is a dangling symlink ... )

as a quick fix (since we are preparing a 15.04 snappy release) i'll rm that file during image build ... i'll leave the bug open since someone should examine where that dangling symlink comes from at all though.

[Barry Warsaw (barry)]

If config.d/00_default.ini -- or probably any ini file -- is a dangling symlink, this bug is probably triggered.

[Barry Warsaw (barry)]

So I have a merge proposal ready to fix this problem, but as I've mentioned in LP: #1495207 two things are still mysterious:

How did you hit this bug when it's only possible in si 3.0, and that version is only available in Wily?

How is the server producing dangling symlinks?

[Launchpad Janitor (janitor)]

This bug was fixed in the package system-image - 3.0.2-0ubuntu1

---------------
system-image (3.0.2-0ubuntu1) wily; urgency=medium

  [ CI Train Bot ]
  * New rebuild forced.

system-image (3.0.2-0ubuntu1) wily; urgency=medium

  * New upstream release.
    - LP: #1495688 - Don't crash when one of the .ini files is a dangling
      symlink.
    - d/rules: override_dh_auto_clean because otherwise, pybuild will
      remove the .egg-info files and that causes the Jenkins job in the CI
      train to fail.

 -- Barry Warsaw <email address hidden> Mon, 28 Sep 2015 21:37:45 +0000